It has been a poor year for women's tennis. The only match of quality at the Australian Open was the quarter-final between Maria Sharapova, who went on to win the title, and Justine Henin of Belgium, who shocked the sport when she hung up her rackets before the French Open. At Roland Garros the standard was generally no better than average, while Wimbledon lost its top four seeds before the quarter-finals, unprecedented in the tournament's history. Then came Saturday's all-Williams final.

This was retro-tennis. The last grand slam final between the sisters was at Wimbledon five years ago, and suddenly it seemed as if the sport had stood still for those 60 months. Venus and Serena are essentially part-time players in terms of the women's circuit. This re-emergence for their seventh grand slam final reinforced the feeling that the strength in depth of the WTA Tour is not what many in charge of the game would crack it up to be, and that the quality at the top is currently thin.

This is to take nothing away from the Williamses. It was the best of their three Wimbledon finals together, and arguably the most enjoyable of them all at this level, with Serena now leading 5-2. There were times when it was quite possible to forget they were sisters, and simply relish the quality and competitiveness of the play without dwelling too much on the complications of sibling rivalry. Venus's victory, her fifth at the All England Club, also emphasised her position as the best grass-court player of her generation, and one of the finest of all time. Name Martina Navratilova, Steffi Graf and Billie Jean King, and Venus Williams links arms with all three now.

The Williamses raised the level of play to new heights at the turn of the millennium, yet their athleticism, combined with ever developing racket and string technology, has become counter-productive.

The first to suffer was Switzerland's Martina Hingis, a five-times grand slam champion, and a player gifted with the more cerebral arts of the tennis court. Had she been a foot taller she might have become one of the greatest champions. Instead she was forced out by a foot injury before making a comeback cut short by failing a drugs test for cocaine.

Belgium's Kim Clijsters, winner of one slam, also found her body could not cope with the rigours of power play and retired early to begin a family, while her countrywoman Henin, the winner of seven majors and as diminutive as Hingis, apparently decided, at the age of 25, that the conflict between ambition and what her body was capable of withstanding had become an unequal fight.

Of those still playing, the Russian Sharapova, a three-times grand slam champion before her 21st birthday, is struggling with a long-term shoulder problem and has hinted she may last no longer than Henin, Jelena Jankovic needs a trainer in residence at all her matches, while her fellow Serb Ana Ivanovic, the French Open champion and world No1, found the task of winning Roland Garros and Wimbledon back-to-back beyond her current physical and emotional capabilities.

The WTA Tour is attempting to address the problem by reducing the number of tournaments next year. The hardcourts of the US, cement-based and totally unforgiving, are frequently blamed for the seemingly increasing number of leg injuries, though perhaps the more pertinent factor is that the intrinsic physical demands of the baseline power game are, at the highest level, beyond the athletic capabilities of the majority of current women players.

Venus and Serena have had more than their share of injuries, but have carefully restricted the tournaments they play beyond anything the WTA has tried to enforce. They have been severely criticised for their absence, while sponsors remain less than happy - Sony Ericsson being unlikely to renew its umbrella contract - but the record books point to eight slams for Serena, and now seven for her sister.

On the clay in Paris neither Venus nor Serena made it beyond the last 32, while at the Australian Open both went out in the quarter-finals. Venus had not won a tournament this year prior to Wimbledon, while Serena's last slam final was when she won in Melbourne in 2007. But they can never be written off. Asked whether Saturday was the beginning of their sisterly second coming, Venus said: "I would love that."